National Semiconductor introduces a 100V half-bridge pulse-width modulation (PWM) controller that offers the industry’s highest level of integration to minimize the overall solution size of half-bridge DC-DC converters. National is demonstrating the LM5035 in booth 8/9 at the Applied Power Electronics Conference (APEC) in Dallas today through Wednesday.

The LM5035, the newest member of National’s high-voltage LM5000 family, integrates a voltage-mode PWM controller with high-side and low-side 2A peak gate drivers plus two programmable, secondary-side synchronous rectifier FET drivers. Programmable control of the rectifying switches allows designers to perfect their timing relationship to optimize overall power efficiency. Applications for LM5035 half-bridge power supplies include telecommunications, data communications and industrial control systems where power density and efficiency are primary concerns.

"Most competitors' half-bridge controllers require an external half-bridge FET driver, which increases the solution footprint and introduces timing errors due to propagation delays," said Paul Greenland, director of strategic marketing for National Semiconductor’s Power Management Group. "With the LM5035, National has integrated core IP from our LM5100A gate driver and LM5025 PWM controller on a single chip. The result is a robust solution with industry-leading power density for highly compact power modules such as one-eighth and one-sixteenth bricks."

About the LM5035
The LM5035 half-bridge controller and gate driver contains all of the features necessary to implement half-bridge-topology power converters using voltage-mode control with line feed-forward. It also includes:
* Synchronous rectifier controls with programmable delays that allow users to optimize power efficiency by tuning the secondary-side and primary-side FET switch timing
* Voltage-mode control for stable operation in half-bridge topology and better noise immunity than current mode control
* Line feed-forward compensation to improve regulation during input line voltage fluctuations
* Resistor-programmed oscillator capable of operating up to 2 MHz
* Synchronization capability to lock the PWM to an external oscillator for reduced electro-magnetic interference
* Programmable line under-voltage lockout to control power-on sequencing and minimize start-up current surges
* Remote thermal sensor interface that directly connects to an external thermister
* Adjustable soft-start for safe start-up in applications with large capacitive loads
* Versatile, dual-mode over-current protection with hiccup delay timer to reduce power dissipation during a continuous load fault
* Cycle-by-cycle over-current limiting to protect power supply components from instantaneous overload conditions
* Unique, current-mode opto-coupler interface that increases the bandwidth of conventional opto-couplers
* Precision 5V output that eliminates the need for an external reference or a bias supply for housekeeping circuits

Available now, the LM5035 is priced at $1.90 in 1,000-unit quantities.